- 2079 Bhadra · 2 marks
Role of Co, Mn, Cr, Ni in steel
Short answer
Cobalt increases red hardness and heat resistance. Manganese adds strength, toughness, and wear resistance while removing sulphur. Chromium provides hardness, wear resistance, and above 11-12% gives stainless steel. Nickel increases strength, toughness at low temperatures, ductility, and corrosion resistance.
What is the role of Cobalt, Manganese, Chromium and Nickel in the respective alloy of steel?
| Element | Role in steel |
|---|---|
| Cobalt (Co) | Increases hardness at high temperature (red hardness) and heat resistance; improves magnetic properties; used in high-speed tool steel and magnets. |
| Manganese (Mn) | Increases strength, hardness, toughness and wear resistance; removes sulphur and oxygen (prevents red shortness); high-Mn steel (12-14%) is used for rail crossings and crushers. |
| Chromium (Cr) | Increases hardness, strength, wear and corrosion resistance; above 11-12% Cr gives stainless steel. |
| Nickel (Ni) | Increases strength and toughness (also at low temperature), ductility and corrosion resistance; with Cr gives austenitic stainless steel. |
✓ Answer checked by Claude Opus 5.5 (high effort)
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